A Republican from the Sixteenth District, the sixty-one year old delegate was engaged in farming and sawmilling in Whatcom.
Born in Scotland in 1828, Eldridge followed the sea until 1849. He mined in California and came to Whatcom, Washington Territory, in 1853. He had held all of the county offices and was speaker of the house in the territorial legislature in 1866. He had been a delegate at the Walla Walla Constitutional Convention of 1878.
Eldridge served on the folowing committees: Revision, Adjustment and Enrollment; State, School and Granted Lands.